It appears I have a DEAD BECM......Possibly......

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zzr1200

zzr1200

Well-Known Member
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Location
Chesterfield, Derbyshire
After 6 years of trouble free P38 ownership it looks like the electrical gremlins have invaded my becm/vehicle.

Used my P38 last weekend no problems, this weekend it all fell apart...:(

Rangie wouldn't unlock from the key fob, manually unlocked the door, ignition on, no dash lights at all, open bonnett, test battery voltage 7 volts with the ignition off (2.3 volts on...:(..), changed the battery and connected jump leads from the firms van (14.0 volts now) to maintain voltage while testing, ignition on, "Engine Disabled"....:(

Plugged in the Extreme to read the EMS code from the EDC no problems, tried to open the BECM to input the code to resync, Vehicle Explorer can't connect to the BECM "No Communications" .....:mad:......but the extreme will connect to all the other ecu's fitted.

Checked all the fuses and that the becm has power to it, being as the extreme can read all the other ecms fitted, I tried using the extreme to open/close windows, turn on/off lights, test speedo, plus other things, no reactions from any input from the extreme, but the lights/windows work from the vehicles controls, I had to recalibrated the windows, with no problems.

Checked the OBD lead with the multimeter against BBS wiring diagram for it, all ok.

Being as all the ecu's can be read apart from the BECM do I have a DEAD BECM or where do I look next vehicle wiring, if so where in/on the vehicles looms????
 
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zzr1200 said:
After 6 years of trouble free P38 ownership it looks like the electrical gremlins have invaded my becm/vehicle.

Used my P38 last weekend no problems, this weekend it all fell apart...:(

Rangie wouldn't unlock from the key fob, manually unlocked the door, ignition on, no dash lights at all, open bonnett, test battery voltage 7 volts with the ignition off (2.3 volts on...:(..), changed the battery and connected jump leads from the firms van (14.0 volts now) to maintain voltage while testing, ignition on, "Engine Disabled"....:(

Plugged in the Extreme to read the EMS code from the EDC no problems, tried to open the BECM to input the code to resync, Vehicle Explorer can't connect to the BECM "No Communications" .....:mad:......but the extreme will connect to all the other ecu's fitted.


Checked all the fuses and that the becm has power to it, being as the extreme can read all the other ecms fitted, I tried using the extreme to open/close windows, turn on/off lights, test speedo, plus other things, no reactions from any input from the extreme, but the lights/windows work from the vehicles controls, I had to recalibrated the windows, with no problems.

Checked the OBD lead with the multimeter against BBS wiring diagram for it, all ok.

Being as all the ecu's can be read apart from the BECM do I have a DEAD BECM or where do I look next vehicle wiring, if so where in/on the vehicles looms????
Click to expand...

Pins 7 & 15 are BECM, other ECU's use different pins.
Wet carpet?
Not sure if the BECM being in an alarmed state locks it out.
They don't like being jumped. Charge the battery.
Could be the RF receiver has gone tits up.

OBD II SOCKET PINOUTS​



Pin 1- (Grey & Red) EAS Timer​

Pin 4- (Black) Ground​

Pin 5- (Black & Purple) Ground​

Pin 7- (Pink & Red) BECM (Socket C 255)​

Pin 11- (White & Light Green) EAS ECU​

Pin 12- (White & Pink) EAS ECU​


Pin 13- SRS? Not shown in RAVE​

Pin 14- (Yellow & Green) Airbag ECU​

Pin 15- (Light Green & Red) BECM (Socket C 255)​

Pin 16- (Brown) 12V+ Feed via 5A fuse (F 33) ​


Wire colours not confirmed.​
 
Datatek said:
Pins 7 & 15 are BECM, other ECU's use different pins.
Wet carpet?
Not sure if the BECM being in an alarmed state locks it out.
They don't like being jumped. Charge the battery.
Could be the RF receiver has gone tits up.

OBD II SOCKET PINOUTS​



Pin 1- (Grey & Red) EAS Timer​

Pin 4- (Black) Ground​

Pin 5- (Black & Purple) Ground​

Pin 7- (Pink & Red) BECM (Socket C 255)​

Pin 11- (White & Light Green) EAS ECU​

Pin 12- (White & Pink) EAS ECU​


Pin 13- SRS? Not shown in RAVE​

Pin 14- (Yellow & Green) Airbag ECU​

Pin 15- (Light Green & Red) BECM (Socket C 255)​

Pin 16- (Brown) 12V+ Feed via 5A fuse (F 33) ​


Wire colours not confirmed.​
Click to expand...

Carpets are dry as far as I can tell.

I changed the battery, only used jump leads to maintain the voltage.

I fitted the latest RF receiver 3 years ago, never had a problem with it but always a possibility.
 
Well, if you have the ignition key in the right position, I'd check the OBD connector.
It's possible the BECM itself is in an alarmed state, you can only deal with that situation with the direct access SM 035 module on the Faultmate.
 
Datatek said:
Well, if you have the ignition key in the right position, I'd check the OBD connector.
It's possible the BECM itself is in an alarmed state, you can only deal with that situation with the direct access SM 035 module on the Faultmate.
Click to expand...

I'II have to recheck the OBD connector and wiring to the becm, if no fault can be found it looks like it maybe time to read up on open heart becm surgery....:eek:


Rick the Pick where are you!!!!!
 
I don't own a Faultmate but I have a Nanocom, so I guess the procedure is the same. To read the BECM I place the key on position 2 but the engine must be off. If it's running the Nanocom won't talk to it.
 
I've been told before from the guys at BBS that best results for connecting to the BECM are to do it with the ignition OFF

I've connected to a bunch of vehicles with my Nanocom, and with the ignition off, it just comes up "DIAGNOSTICS MODE" on the instrument panel. It does work with the ignition on too, but as I was just told that most reliable communications are without ignition on at all.

Also another place to check is the kick panel in the driver's footwell (RHD) where the interia switch is located. In behind there are a couple of connectors that get green and corroded, and the diagnostic lines that go to the BECM go through one of the connectors.

If you can talk to the transmission (communications go through the BECM) then it may mean the connectors are OK, but can't hurt to check. On petrol models, only one diagnostic line is used on the Autobox ECU - on diesels, both lines are used.

I read a BECM on a vehicle that has been sitting for months today - Could access it, but had a while load of weird settings come up (like being set to French language) - which leads me to believe it's locked out, but I could still talk to it.

HTH
 
martyuk said:
I've been told before from the guys at BBS that best results for connecting to the BECM are to do it with the ignition OFF

I've connected to a bunch of vehicles with my Nanocom, and with the ignition off, it just comes up "DIAGNOSTICS MODE" on the instrument panel. It does work with the ignition on too, but as I was just told that most reliable communications are without ignition on at all.

Also another place to check is the kick panel in the driver's footwell (RHD) where the interia switch is located. In behind there are a couple of connectors that get green and corroded, and the diagnostic lines that go to the BECM go through one of the connectors.

If you can talk to the transmission (communications go through the BECM) then it may mean the connectors are OK, but can't hurt to check. On petrol models, only one diagnostic line is used on the Autobox ECU - on diesels, both lines are used.

I read a BECM on a vehicle that has been sitting for months today - Could access it, but had a while load of weird settings come up (like being set to French language) - which leads me to believe it's locked out, but I could still talk to it.

HTH
Click to expand...

I'II try all key switch positions for diagnostics connection later today.

Its going to be difficult to read an auto box ecu being as its a manual gearbox rangie, as I cant access the becm theres no switching status for the transfer box to be read either.

Attached is the ecu's that can be read....

Aren't rangie electrics wonderful......
 

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zzr1200 said:
I'II try all key switch positions for diagnostics connection later today.

Its going to be difficult to read an auto box ecu being as its a manual gearbox rangie, as I cant access the becm theres no switching status for the transfer box to be read either.

Attached is the ecu's that can be read....

Aren't rangie electrics wonderful......
Click to expand...

Sorry - didn't know it was a manual - in that case, definitely check out the connectors in the drivers kick panel. They are known to corrode, and the diagnostic wires to the BECM go through to them.

If you're handy with a multimeter, then you can unplug the connector at the BECM that the diagnostic wires go into (white, 20way under and to the right of the fuse box) and check for continuity back to the relavant pins on the OBD socket - to make sure there's a solid connection with no resistance.

There's also a couple of splices for the diagnostic wires in the loom that goes under the heater box - if the heater core has leaked in the past it could have gotten in and corroded the splice - but I would expect to see issues with communications to other ECU's.

I have a mate with a P38, and we can't talk to his BECM with my Nanocom - and he has phantom battery drain - not from RF either it seems, which points to an internal problem to the BECM (It's going for a holiday to Brighton soon). Aside from that, his BECM works perfectly fine - all functions work and are controlled as they should be.

Marty
 
Went out to my mates Range Rover again this morning, to resync it, no problem so my extreme and leads are working.

Returned home tried to gain access to my becm again, "no communications" on the laptop shown, all other ecu are still readable, reset the windows after battery disconnection, plus all the cabin controls work, except engine start...

When the ignition is "turned on" the following message moves across the instrument pod,
" press key fob or enter key code" are they asking for the EKA code or the FOB code programmed into the BECM which requires it to be unlocked.

I've entered the EKA code by the door key/lock method, with the beeps all place.

I had to pack up early today so, I'm hoping that its a bad connection in the wiring between the OBD socket and the BECM, as stated above there's a connection plug behind the r/hand kick panel that corrodes, is there any other connector/s to search out and check as well...

Or is it down to removing the becm for open heart surgery...

Advise from those who have been down this road before would be appreciated, please...
 
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From all the digging through wiring I've done on my mates P38 - the only connector the diagnostic lines go through are via the footwell kick panel connectors - Looking in the ETM again (now I'm back home with the laptop in front of me), the BECM is actually connected straight through from the splice under the dash. The footwell connectors go on to the ABS ECU and Engine ECU. Which putting that in perspective, are probably OK if you can talk to the engine ECU/ABS ECU's.

The best way to test the wires to the BECM would be to check the continuity with a multimeter from the OBD connector through to the BECM connector under the fuse box. If you get a solid connection, no high resistance, then the issue is obviously internal to the BECM.

The message that comes up on the dash is asking for the EKA code. The FOB code for the BECM is just an identifier of the FOB to make sure it is the one programmed to that vehicle.

If your EKA code won't be accepted, then it would be worth testing the door latch to make sure all the microswitches are working - if either the CDL or Key Switches have failed, then it could mean the EKA won't work. There's also a couple of other connectors inside the vehicle side of the door jamb that can get corroded and cause intermittent communication from the door outstation.

If that checks out then it could be the BECM has gone into lockdown, and needs to be sent away for unlocking/resetting. In theory the later versions of BECM (from Software version 36) can have the EKA input from Faultmate/Nanocom - but that of course requires diagnostic communications!

Check the kick panel connectors (just to be sure), and make sure the diagnostic lines to the BECM are all good - then if still no diagnostic connection, then it might be time to send the BECM off.
 
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